Control knob for digital shower system



FIG. 1 is a perspective view of a control knob for digital shower systemshowing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The ornamental design for a control knob for digital shower system, asshown and described.